摘要
光伏并网逆变器在电网发生不对称故障时,其注入到电网中的电流将是非正弦或不对称的,传输至电网的有功、无功功率也会产生不可控振荡。为了抑制电网不对称故障对光伏系统输出电流及功率造成的影响,在传统解决方案—基于解耦双同步旋转坐标系(Decoupled Double Synchronous Reference Frame,DDSRF)控制策略的基础上,提出一种带前馈和附加反馈环的改进型DDSRF控制策略。该方法可在电网不对称故障下准确地检测出并网电流的正、负序直流分量,加快实现测量电流对参考电流的零稳态误差跟踪。利用实时数字仿真器(Real Time Digital Simulator,RTDS)搭建的光伏并网发电系统试验平台,对传统DDSRF控制器和改进型DDSRF控制器的控制性能进行了对比论证。试验结果证明了所述新型控制器提高了系统的动态性能,增强了光伏并网逆变器的不对称故障穿越能力。
The unsymmetrical grid faults will cause non-sinusoidal or asymmetric output current of the Photovoltaie （PV） grid-connected inverter, also they will lead to the ripple in the active and reactive power. In order to suppress the effects on the current and power, a new control strategy called DDSRF with feed-forward and additional feedback loop is proposed based on the classical DDSRF controller in this paper. The improved controller can detect the positive and negative sequence components of grid current precisely, and make the measured values tracking for the references quickly. It will improve the performance of the PV grid-connected inverters during the transient process of the unbalanced grid voltage fault condition, and its fault ride through capability will be enhanced as well. A PV grid-connected power system test platform is established based on RTDS, and test results demonstrate the validity of the improved DDSRF controller.
出处
《控制工程》
CSCD
北大核心
2015年第3期439-446,共8页
Control Engineering of China
基金
国家863高技术基金项目(2012AA050206)
